public AutoJSContext()
{
nsIJSRuntimeService runtimeService = (nsIJSRuntimeService)Xpcom.GetService("@mozilla.org/js/xpc/RuntimeService;1");
IntPtr jsRuntime = runtimeService.GetRuntime();
IntPtr cx = JS_NewContext(jsRuntime, 8192);
nsIJSContextStack contextStack = Xpcom.GetService <nsIJSContextStack>("@mozilla.org/js/xpc/ContextStack;1");
contextStack.Push(cx);
nsIPrincipal system = Xpcom.GetService <nsIScriptSecurityManager>("@mozilla.org/scriptsecuritymanager;1").GetSystemPrincipal();
IntPtr jsPrincipals = system.GetJSPrincipals(cx);
JSStackFrame frame = new JSStackFrame();
frame.script = JS_CompileScriptForPrincipals(cx, JS_GetGlobalObject(cx), jsPrincipals, "", 0, "", 1);
//NOTE: this code is based on the definition of JSContext from mozilla 1.8 and will not work for other versions
IntPtr old = Marshal.ReadIntPtr(cx, 0x34);
frame.down = old;
IntPtr framePtr = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(JSStackFrame)));
Marshal.StructureToPtr(frame, framePtr, true);
// cx->fp = framePtr;
Marshal.WriteIntPtr(cx, 0x34, framePtr);
}
public AutoJSContext()
{
// obtain the JS runtime used by gecko
nsIJSRuntimeService runtimeService = (nsIJSRuntimeService)Xpcom.GetService("@mozilla.org/js/xpc/RuntimeService;1");
IntPtr jsRuntime = runtimeService.GetRuntimeAttribute();
// create a new JSContext
cx = JS_NewContext(jsRuntime, 8192);
// begin a new request
JS_BeginRequest(cx);
// push the context onto the context stack
nsIJSContextStack contextStack = Xpcom.GetService <nsIJSContextStack>("@mozilla.org/js/xpc/ContextStack;1");
contextStack.Push(cx);
// obtain the system principal (no security checks) which we will use when compiling the empty script below
nsIPrincipal system = Xpcom.GetService <nsIScriptSecurityManager>("@mozilla.org/scriptsecuritymanager;1").GetSystemPrincipal();
IntPtr jsPrincipals = system.GetJSPrincipals(cx);
// create a fake stack frame
JSStackFrame frame = new JSStackFrame();
frame.script = JS_CompileScriptForPrincipals(cx, JS_GetGlobalObject(cx), jsPrincipals, "", 0, "", 1);
// put a pointer to the fake stack frame on the JSContext
// frame.down = cx->fp
IntPtr old = Marshal.ReadIntPtr(cx, OfsetOfFP);
frame.down = old;
IntPtr framePtr = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(JSStackFrame)));
Marshal.StructureToPtr(frame, framePtr, true);
// cx->fp = framePtr;
Marshal.WriteIntPtr(cx, OfsetOfFP, framePtr);
}
/// <summary>
/// Add hooks to listen for new JSContext creation and store the context for later use.
/// This is the only way I have found of getting hold of the real JSContext
/// </summary>
protected void RecordNewJsContext()
{
Xpcom.AssertCorrectThread();
// Add a hook to record when the a new Context is created.
// If an existing hook exists, replace hook with one that
// 1. call original hook
// 2. reinstates original hook when done.
_runtimeService = Xpcom.GetService<nsIJSRuntimeService>("@mozilla.org/js/xpc/RuntimeService;1");
_jsRuntime = _runtimeService.GetRuntimeAttribute();
_managedCallback = (IntPtr cx, UInt32 unitN) => { JSContext = cx; SpiderMonkey.JS_SetContextCallback(_jsRuntime, null); return 1; };
_originalContextCallBack = SpiderMonkey.JS_SetContextCallback(_jsRuntime, _managedCallback);
if (_originalContextCallBack != null)
{
RemoveJsContextCallBack();
_managedCallback = (IntPtr cx, UInt32 unitN) => { JSContext = cx; SpiderMonkey.JS_SetContextCallback(_jsRuntime, _originalContextCallBack); return _originalContextCallBack(cx, unitN); };
SpiderMonkey.JS_SetContextCallback(_jsRuntime, _managedCallback);
}
}
